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  • Calculate the size of a DNS record in the cache

    From Mik J@21:1/5 to All on Tue Jul 28 22:47:46 2020
    Hello,
    My cache is 100MB and I'd like to know how many records can fit inside.I suppose that it depends on the record: isc.org is 7 characters and shorter than http://www.example.com
    And it probably depends on the type and adress.
    So which size would isc.org A 1.1.1.1 be ?

    I ask my question because I was wondering how many nxdomainattack000000001.example.com, nxdomainattack000000002.example.com...can I generate before fil in the cache of my recursive server
    According to the RFC, if my example.com SOA TTL is 86400, the NXDOMAIN entry would remain in the cache for 1 day.
    Thank you for sharing your thoughts



    <html><head></head><body><div class="ydpe277e8byahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div dir="ltr" data-setdir="false">Hello,</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr"
    data-setdir="false">My cache is 100MB and I'd like to know how many records can fit inside.</div><div dir="ltr" data-setdir="false">I suppose that it depends on the record: isc.org is 7 characters and shorter than <a href="http://www.example.com" rel="
    nofollow" target="_blank">http://www.example.com</a></div><div><br></div><div>And it probably depends on the type and adress.</div><div><br></div><div dir="ltr" data-setdir="false">So which size would isc.org A 1.1.1.1 be ?<br></div><div><br></div><div
    dir="ltr" data-setdir="false">I ask my question because I was wondering how many nxdomainattack000000001.example.com, <span>nxdomainattack000000002.example.com...can I generate before fil in the cache of my recursive server</span></div><div dir="ltr"
    data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span>According to the RFC, if my example.com SOA TTL is 86400, the NXDOMAIN entry would remain in the cache for 1 day.</span></div><div dir="ltr" data-setdir="false"><span><br>
    </span></div><div dir="ltr" data-setdir="false"><span>Thank you for sharing your thoughts</span><br></div><div><br></div><div dir="ltr" data-setdir="false"><br></div></div></body></html>

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